Vibrator driven timepiece



{Jul 19, 1966 M; HETZEL 3,261,158

VIBRATOR DRIVEN TIMEPIECE Filed May 2'7, 1965 F162 FIC5.3 FIGA F'|G.5

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FIG.6 Fl6.7 F|G.8 PIC-3.9

United States Patent 3,261,158 VIBRATOR DRIVEN TIMEPIECE Max Hetzel, Bienne, Switzerland, assignor to Centre Elecn'onique Horloger S.A., Neuchatel, Switzerland Filed May 27, 1965, Ser. No. 459,177 Claims priority, application Switzerland, May 28, 1964, 6,991/64 4 Claims. (Cl. 58-23) Certain timepieces, such as electronic watches, comprise a mechanical oscillator, which may be in the form of a diapason or tuning fork, or of a vibrating blade, or even of a torsion lever, and which exercises the functions simultaneously of a regulating member and of a driving means. These oscillators, which may vibrate at frequencies of some tens to some thousands of oscillations per second, usually exercise their driving function through the medium of a pawl co-operating with a rachet wheel, the first wheel of a minute-wheel train. The pawl and the ratchet wheel constitute, on the one hand, a motion-transformer, since they change an alternating movement into a continuous rotary motion, and, on the other hand, a frequency-divider, for a large number of vibrations of the oscillator occasion only a small number of revolutions of the wheel, or even only a fraction of a revolution.

These devices, which have been tested in various constructions, always exhibit disadvantages, essentially owing to the fact that the oscillator, once every cycle, has to set in motion a wheelwork which has a high moment of inertia. This function creates a periodical disturbance of the oscillation, and increases, in proportions that are not negligible, the consumption of electrical energy.

Attempts have been made to remedy these defects by reducing the dimensions of the wheelwork. This solution is only a make-shift, for the excessive moment of inertia is replaced by difficulties of manufacture.

The present invention, which is free from the abovementioned disadvantages, relates to a timepiece in which the regulating and motor member is constituted by a mechanical oscillator, which actuates, through a catch on a wheel, a first ratchet wheel. It is characterized by a cam, fixed upon this ratchet wheel, by a three-armed lever, preferably balanced, upon one arm of which there acts a restoring spring, while to its second arm is fixed a resilient blade, and on its third arm is mounted a second pawl, by a minute-wheel wheelwork, of which the first wheel is a catch wheel, all for the purpose that the mechanical oscillator that drives the first ratchet wheel, the cam, rigid with the latter, may displace the lever against the action of its restoring spring and then abandon it, the lever returning suddenly to its initial position, carrying the minutes wheel along by the second of the abovementioned pawls.

One form of construction of the invention is illustrated by way of example in the accompanying drawings, in which:

FIGURE 1 is a view in plan; and

FIGURES 2 to 9 show modifications of detail.

In this form of construction, an oscillator, partially represented at 1, having an alternating motion in the direction of the arrows 2, supports a pawl formed of a blade 3 and a jewelled pallet 4. The latter drives a ratchet wheel 5, having a large number of teeth in the form of an isosceles triangle. On its shaft is fixed a cam 6, having five teeth. A second pawl, fixed to the watch frame, comprising a blade 7 and a jewelled pallet 8, plays the part of a retaining member, immobilising the wheel when it is not being driven by the oscillator. A lever 9, pivoted by its shaft 10 in the watch frame, presents three arms 9a, 9b and 90. Two fixed abutments 11 and 12 limit its angular displacements. A resilient blade 13 is an extension of the arm 9a, and comes into contact with the teeth of the cam 6. A helical spring 14 is fixed by one of its ends to the arm 9b, and by the other to the frame. The arm 9c carries, at its end, a pawl comprising a blade 15 and a jewelled pallet 16, which co-operates with a ratchet wheel 17, the first wheel of the minutewheel wheel'work, which is continued by the wheels 18 and 19. A pawl formed by a blade 20 and a jewelled pallet 21 prevents any rotation of the minute-wheel wheelwork in the opposite direction. A stop lever 22 displaceable in the direction of the arrows 23, and capable of being actuated from the exterior of the watch, by means of a member not illustrated, enables the lever 9 to be immobilised by pressing its arm 9a against the abutment 11. i

This device operates in the following manner: When the oscillator 1 vibrates, the pawl 3, 4 drives the ratchet wheel 5, and the cam 6 which is solid with it, in a jerky rotational movement. At each fifth of a revolution of the cam, one tooth of the latter meets the resilient blade 13 and drives it, slightly bending it.

The lever 9 is then displaced in its position of stoppage, for instance against the abutment 11, Whilst the helical spring 14 has been cocked, and the pawl 15, 16 has recoiled by at least one tooth upon the ratchet wheel 17. At the moment when the cam releases the extremity of the spring blade 13, the spring 14 suddenly returns the lever 9 to its position of bearing against the abutment 12, and the pawl 15, 16 drives the ratchet wheel 17 at least one tooth.

The spring blade 13 presents a slight bending moment, and the lever 9 possesses a great moment of inertia, so that during the periods of driving of the lever by the cam 6, the spring is displaced with a jerky movement, while the lever has a continuous movement. Under these conditions, only the moments of inertia of the spring blade, the ratchet wheel 5 and the cam 6 disturb the vibrations of the oscillator.

By adopting, for the oscillator, a frequency of 480 vibrations per second, and providing the wheel 5 with 240 teeth and the cam 6 with five teeth, it will :be seen that the Wheel 5 executes two revolutions per second, and that at every tenth of a second the lever 9 executes one oscillation. The wheelwork of the minute wheel is thus driven ten times per second. The seconds hand therefore has the possibility of indicating, by successive jumps, tenths of a second.

In constructional modifications, and for the purpose of ensuring greater division of frequency between the oscillator 1 and the lever 9, the cam may have four teeth, .as represented by FIGURE 2, three teeth as shown in FIGURE 3, or even two teeth as shown by FIGURE 4. In fact the greatest division of frequency is realized with the comma-shaped cam of FIGURE 5.

All these ca ms work with the extremity of the spring blade 13, which should then have a very precise length in order to ensure its functioning. On the other hand, the friction is a minimum, since the contact is periodical, and the cam drives the spring blade in the manner of toothed gearing.

Finally, the cams may have the forms shown by FIG- URES 6, 7, 8 and 9, no longer working with the extremity of the spring blade but with one of its sides. In this way the driving function is independent of the length of the spring. Nevertheless the friction is permanent between the cam and the spring blade.

When a great division of frequency between the oscillator and the lever is realised, the ratchet wheel 17 may consitute the seconds wheel. In point of fact, by adopting, as in the first example, a frequency of 480 vibrations per second for the oscillator and 240 teeth for the wheel 5, and by placing on this wheel a cam with one tooth, the

lever 9 executes two oscillations per second. If the wheel 17 is provided with 120 teeth, it may be fixed to 3. seconds hand, which will advance at every half-second.

In order to reduce the space in height occupied by this device, it is possible to replace the helical spring by a wire spring, and to compensate for the smallness of the force of the latter by increasing the length of the arm 9b.

The stop lever 22 provides the possibility of immobilising the lever 9 against the abutment 1 2 without the vibrations of the oscillator being interrupted. In this way it is easily possible to execute any setting operation, or even to stop or re-start the timepiece for the purpose of measuring an interval of time.

I claim: a

1. A timepiece the regulating and driving member of which is constituted by a mechanical oscillator (1), actuating, through a catch device, a first ratchet wheel (5), characterised by a cam (6), fixed upon this ratchet wheel; by a three-armed lever (9), upon one arm of which there acts a restoring spring (14), while upon its second arm is fixed a resilient blade (13), and upon the third arm is mounted a second pawl (15); and by a minutes wheelwork, of which the first wheel (17) is a second ratchet wheel, upon which there acts this second pawl; all in order that the mechanical oscillator driving the first ratchet wheel, the cam rigid with the latter may displace the lever against the action of its restoring spring, and may then abandon the lever, returning briskly to its initial position, and carrying the minutes wheel along by the second abovementio-ned pawl.

2. A timepiece as claimed in claim 1, wherein the second ratchet wheel (17 constitutes the seconds wheel.

3. A timepiece as claimed in claim 1, wherein a stop lever (22) acts upon the said lever (9) in order to immobilise it in a position for which the spring blade (13) is no longer being actuated by the cam (6).

4. A timepiece as claimed in claim 1, wherein the lever (9), deprived of its spring (14), is balanced.

No references cited.

RICHARD B. WILKINSON, Primary Examiner.

GERALD F. BAKER, Examiner. 

1. A TIMEPIECE THE REGULATING AND DRIVING MEMBER OF WHICH IS CONSTITUTED BY A MECHANICAL OSCILLATOR (1), ACTUATING, THROUGH A CATCH DEVICE, A FIRST RATCHET WHEEL; CHARACTERISED BY A CAM (6) , FIXED UPON THIS RATCHET WHEEL; BY A THREE-ARMED LEVER (9), UPON ONE ARM OF WHICH THERE ACTS A RESTORING SPRING (14), WHILE UPON ITS SECOND ARM IS FIXED A RESILIENT BLADE (13), AND UPON THE THIRD ARM IS MOUNTED A SECOND PAWL (15); AND BY A MINUTES WHEELWORK, OF WHICH THE FIRST WHEEL (17) IS A SECOND RATCHET WHEEL, UPON THERE ACTS THIS SECOND PAWL; ALL IN ORDER THAT THE MECHANICAL OSCILLATOR DRIVING THE FIRST RATCHET WHEEL, THE CAM RIGID WITH THE LATTER MAY DISPLACE THE LEVER AGAINST THE ACTION OF ITS RESTORING SPRING, AND 